Best Heater for Small Greenhouse

A small greenhouse can produce big results—but only if you keep it warm when temperatures drop. Whether you’re starting seeds in spring or growing year-round in a cold climate, the right heater for a small greenhouse makes all the difference. It ensures your plants stay cozy, your seedlings germinate faster, and your efforts don’t freeze overnight.

In this guide, we’ll break down the best heaters for small greenhouses in 2025—from budget-friendly electric models to safe, off-grid propane options. Let’s heat things up and find the perfect match for your mini garden space.

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What Qualifies as a “Small” Greenhouse?

In this context, we’re talking about greenhouses under 150 square feet, often around 6×4 to 8×10 feet in size. These include:

• Walk-in mini greenhouses

• Portable greenhouses

• Balcony or patio setups

• Seedling houses

Small greenhouses heat up faster, but also lose heat quickly—so choosing an efficient, compact, and safe heater is key.

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Best Overall Heater for Small Greenhouses

Bio Green PAL 2.0/US Palma Heater

Best for: Most small greenhouse setups (up to 120 sq. ft.)

Direct answer: The Bio Green Palma is the best all-around heater for small greenhouses, offering excellent heat output, built-in thermostat, and greenhouse-specific design.

Top features:

• 1500W electric power—heats up to 120 sq. ft.

• Built-in digital thermostat from 32°F to 100°F

• Splash-proof housing (IPX4 rated)

• Stainless steel design with fan for even heat distribution

• Compact size: easy to position on the ground or low shelf

It’s reliable, precise, and efficient—ideal for seed starting, overwintering, and tropicals in compact spaces.

Power source: Electric
Price range: $150–$200

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Best Budget Heater for Small Greenhouse

Vornado MVH Vortex Heater

Best for: Budget-conscious growers with insulated greenhouses

Direct answer: The Vornado MVH is a powerful yet affordable electric heater that’s ideal for use in dry, well-sealed small greenhouses.

Highlights:

• Three heat settings (750W, 1125W, 1500W)

• Tip-over and overheat protection

• Compact and lightweight

• Quiet operation

Note: It’s not water-resistant, so it should only be used in dry areas or with care inside covered greenhouses.

Power source: Electric
Price range: $40–$70

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Best Heater for Off-Grid Small Greenhouse

Mr. Heater Little Buddy MH4B

Best for: Small, off-grid or non-electric greenhouses

Direct answer: The Mr. Heater Little Buddy is the best propane heater for small greenhouses without electricity, offering safe and portable heat up to 95 sq. ft.

What makes it great:

• 3,800 BTU output

• Runs up to 5.5 hours on a 1 lb propane cylinder

• Tip-over safety shutoff

• Oxygen Depletion Sensor (ODS)

It’s a compact, no-power-needed solution that’s ideal for unheated spaces or backup emergency heat.

Power source: Propane
Price range: $80–$100

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Best Smart-Control Heater for Small Greenhouse

Heat Storm HS-1500-PHX-WIFI Infrared Heater

Best for: Tech-savvy growers who want app-based control

Direct answer: The Heat Storm PHX WiFi heater offers smart control, compact infrared heating, and efficient warmth for small greenhouse spaces.

Top features:

• 1500W infrared heater

• WiFi app control with built-in thermostat

• Wall-mount or freestanding design

• Quiet and efficient radiant heat

This model is ideal for growers who want automation, remote access, or precision scheduling from their phone.

Power source: Electric
Price range: $150–$180

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Best Compact Fan Heater for Air Circulation

Dr. Heater DR218 Greenhouse Heater

Best for: Heat plus air movement in small spaces

Direct answer: The Dr. Heater DR218 is built specifically for greenhouse use, combining heat and a circulation fan in a compact, IPX4-rated shell.

Why it works:

• 1500W heating capacity

• Thermostat control (dial-based)

• IPX4 water-resistant design

• Rugged and industrial-grade build

If you need airflow to prevent mold and hotspots along with steady warmth, this one’s a solid option.

Power source: Electric
Price range: $100–$140

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Comparison Table: Best Small Greenhouse Heaters

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What to Look for in a Small Greenhouse Heater

1. Heating Capacity

• Match wattage to your space. Most 1500W electric heaters can handle up to 150 sq. ft. in a sealed greenhouse.

• Consider insulation quality—uninsulated plastic greenhouses lose heat faster.

2. Thermostat Control

• Built-in thermostats keep temperatures consistent and energy-efficient.

• External smart plugs can add automation to budget models.

3. Safety Features

• Look for tip-over protection, overheat shutoff, and moisture resistance.

• For propane models, make sure they include ODS (Oxygen Depletion Sensor).

4. Air Circulation

• Heaters with fans help distribute heat evenly and reduce humidity buildup.

• Some infrared models heat objects directly—best for tightly enclosed spaces.

5. Ease of Setup

• Electric heaters are plug-and-play.

• Propane models may need ventilation and fuel refills but are great for remote areas.

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Conclusion: Small Greenhouse, Big Potential

A small greenhouse gives you huge advantages in gardening, but only if it’s warm enough to keep your plants alive and thriving. With the right heater, you’ll unlock consistent growth, earlier starts, and protection from cold snaps.

Top picks at a glance:

• Best overall: Bio Green Palma

• Best budget option: Vornado MVH

• Best off-grid heater: Mr. Heater Little Buddy

• Best smart-controlled heater: Heat Storm PHX WiFi

• Best for heat + airflow: Dr. Heater DR218

Still unsure which heater fits your setup? Drop your greenhouse size and climate zone in the comments—I’ll help you choose the perfect heater to keep your garden warm and growing strong all year long